OS or YS decision to make for Freya 60/70 (UK dealer)

[mf_read]

Folks,

I have a Hirobo Freya machine with an new OS 70 engine installed and a CY MPII. I have had several problem in achieving the desired tuning from this setup. I'm using Magnum 12.5% and basically the pistons keep cracking with this setup.

I thought I followed the correct rich run in process and I have not obtained a great climb out yet, My engine cutout in flight at the weekend and I did not have any more time to change the plug etc... After discussions with other members at our club it was agreed that I should pursue another pipe as the MPII does not appear to be giving me the correct setup.

I ordered a Hatori 999 pipe and I removed the MPII pipe today, had a small look through the exhaust and discovered that the piston is broken inside. This has happened within 3 tanks of fuel, and to my knowledge I have not been running it lean.

Irvine/Ripmax have agreed to replace the engine under warranty :D

But, I've lost faith a little in this engine, should I go for the YS 61 ST2 engine? or should I keep the replaced OS 70 SZH? If I choose YS who in the UK supply them?

I may have just been unlucky with this engine but this is the second one in 4 months which has failed on me. I of course could be the problem!!

[DebianDog]

I have (or had) 5 OS motors including the new Hyper 50. I just got (1) old YS-80 motor when I purchased a used copter a few month back. It runs consistently and smoothly... always... from start to finish.

I just purchased a YS-90 because I was so impressed I wanted to see what the new motor will do. Not sure about the UK dealer.

[pilotError]

The OS70 has more power than a ys61.

Stick with it, you'll get it right eventually.

Did you think about changing fuels?

[Alfred]

As I have both and both are installed in X-Cells, I can tell you that the OS70 has beyond a doubt more power.

My OS 70 is mounted with a MP2 and runs very well on 20% Nitro. I do keep it rich.
Me and the YS61ST-2 never became great friends, but it's power did increase once I changed mufflers from SB10 to MP2.

The OS70 is installed in a Fury Expert and the YS61 is installed in a older X-Cell 60.

I wonder if you are comparing yours with a Freya 90?
You basically have the same frame with a smaller engine, ergo..less climbing power.
I have no issues with the OS70 except that it goes slightly lean at the bottom of the tank, which requires to be compansated by running it fairly rich with a full tank to start with.
Mine is just being pulled apart due to a noisy big end bearing but also has seen a lot of flights.

[mf_read]

Thanks for the replies.

I think I'll stick with the OS then.

If I dont get it right this time I'm going electric!!

Thanks again
Mike.